Semiconductor inspecting apparatus

ABSTRACT

In the case of inspecting samples having different sizes by means of a semiconductor inspecting apparatus, a primary electron beam bends since distribution is disturbed on an equipotential surface at the vicinity of the sample at the time of inspecting vicinities of the sample, and what is called a positional shift is generated. A potential correcting electrode is arranged outside the sample and at a position lower than the sample lower surface, and a potential lower than that of the sample is applied. Furthermore, a voltage to be applied to the potential correcting electrode is controlled corresponding to a distance between the inspecting position and a sample outer end, sample thickness and irradiation conditions of the primary electron beam.

This application is a continuation of U.S. patent application Ser. No.13/537,463, filed Jun. 29, 2012, which is a U.S. patent application Ser.No. 13/000,461, filed Dec. 21, 2010, now U.S. Pat. No. 8,232,522, whichis a 371 of international Application No. PCT/JP2009/002860, filed Jun.23, 2009, and which claims priority to Japanese Application No.2008-165757, filed Jun. 25, 2008.

TECHNICAL FIELD

The present invention relates to a semiconductor inspecting apparatususing a charged particle beam used for manufacturing a semiconductordevice.

BACKGROUND ART

In order to measure a dimension of contact holes between wiring layersor gate electrodes in manufacturing a semiconductor device, aninspecting apparatus using a primary electron beam such as acritical-dimension scanning electron microscope (hereinafter, referredto as a CD-SEM) has been used as one type of charged particle beamapplication apparatuses.

Herein, FIG. 14 schematically shows an electron optical system of an SEMsemiconductor inspecting apparatus used in the related art.

A primary electron beam 22 (shown by a dotted line) from an electron gun1 by a voltage from an extraction electrode 2 is converged and deflectedby passing through a condenser lens 3, a scanning deflector 5, anaperture 6, an objective lens 9, or the like, and is then irradiated atan inspecting position of a sample 10, i.e., a semiconductor device,etc. In addition, the condenser lens 3, the scanning deflector 5, theaperture 6, the objective lens 9, and a shield electrode 16 are formedin an axial symmetry shape based on an optical axis 18 as a centralaxis.

The sample 10 is applied with a deceleration voltage (hereinafter,referred to as a retarding voltage) from a retarding power supply 26 fordecelerating the primary electron beam 22. A secondary electron beam 24(shown by a dotted line) is generated from the sample 10 by irradiatingthe primary electron beam 22 and is accelerated by the retarding voltageapplied to the sample 10 to be moved upward. The accelerated secondaryelectron beam 24 is deflected by an E cross B deflector 8 and is theninput to a secondary electron detector 14. The secondary electrondetector 14 converts the input secondary electron beam 24 into anelectric signal, which is in turn amplified by a pre-amp (not shown) toa luminance modulating input for an inspection image signal, therebyobtaining an image data of an inspection region.

In manufacturing the semiconductor device, the sample 10 is asemiconductor wafer and plural rectangular chips are formed almost overthe whole region of the sample 10. For this reason, the inspectingapparatus may perform the inspection on the chip at the central portionof the sample 10 as well as the chip formed at the peripheral portion.In the case of inspecting portions (for example, central portion) otherthan the outer peripheral portion of the sample 10, a equipotentialsurface of the vicinity of the sample 10 has an axial symmetrydistribution using the optical axis 18 as the central axis, but in thecase of inspecting the outer peripheral portion of the sample 10, thereis a problem in that the axial symmetry of the equipotential surface 20(shown by a dotted line) of the vicinity of the sample 10 is disorderedas shown in FIG. 15. When the axial symmetry of the equipotentialsurface 20 is disordered, there is a problem in that the case in whichthe primary electron beam 22 is bent and the primary electron beam 22arrives at a position 30 spaced apart from a position (a position wherethe optical axis 18 and the surface of the sample 10 intersects witheach other) to be originally inspected on the sample 10, that is, aso-called, a position deviation occurs.

In the CD-SEM, the positions to be measured are detected by performingan approximate position adjustment using a mechanical stage and then, ahigh-precision position adjustment using the SEM phase. However, whenthe position deviation is large, the movement amount to the positions tobe measured is increased since the position adjusted by using themechanical stage and the position adjusted by using the SEM phase arefar away from each other, thereby causing the degradation in throughput.

The diameter of the semiconductor wafer that is sample is increased,like a diameter of 300 mm or 450 mm. When the diameter of thesemiconductor wafer is increased, the curvature in the outer edgethereof is small, such that it is possible to form rectangular devicechips formed on the wafer to be further approximate to the outer edge ofthe semiconductor wafer than before. Accordingly, there is a need toinspect the outer edge as maximally as possible, than before, inmanufacturing the semiconductor device. It is known that theabove-mentioned position deviation amount is increased as the positionto be inspected is at the outer edge of the semiconductor wafer. Theproblem of the position deviation that causes the bending of the primaryelectron beam is considered as a more important matter.

As a technology for preventing the disorder of the axial symmetry of theequipotential surface 20 at the outer peripheral portion of the sample,a technology of installing a conductive ring between an edge of thesample (herein, a substrate) and a substrate holder formed at the sameheight as the surface of the substrate that is the sample and applyingvoltage to the conductive ring is disclosed in Patent Document 1.Further, the technology controls the voltage applied to the conductivering according to the gap size between the substrate edge and thesubstrate holder. It is possible to prevent the potential distributionfrom being disordered near the substrate by adopting the technology.

PRIOR ART DOCUMENTS Patent Document

-   Patent Document 1: Japanese Patent Application Laid-Open Publication    No. 2004-235149

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

However, some dimensional errors are inevitable during the manufacturingof the substrate holder, such that there is ruggedness or waviness onthe surface of the substrate holder. In addition, when the substrateholder is installed in the stage by a bolt, or the like, the substrateholder is deformed to the tightened degree. Likewise, there is aprobability of causing the ruggedness or the waviness on the surface.These cause the difference between the surface height of the substrateand the surface height of the substrate holder according to theinspection positions (for example, a position at 12 o'clock and aposition at 3 o'clock) of the substrate edge. In this case, even thoughthe voltage applied to the conductive ring is controlled according tothe gap size between the substrate edge and the substrate holder, thedisorder of the potential distribution near the substrate cannot becompletely corrected. In addition, since the dimensional errors of theplural substrate holders are also inevitable, the difference between thesurface height of the substrate according to the observation position ofthe substrate edge and the surface height of the substrate holder occursby the individual difference of the substrate holder.

As a result, when comparing the plural inspecting apparatuses, thedifference in the disorder of the potential distribution near thesubstrate occurs, such that there is a probability of causing theindividual difference of the inspecting apparatus (the differencebetween the apparatuses). In addition, there may be a case of inspectingvarious samples, for example, the bent semiconductor substrate as thesample during the semiconductor manufacturing. Even in the case,likewise the above-mentioned case, since the difference in the surfaceheight of the substrate at the edge occurs according to the inspectionposition (for example, a position at 12 o'clock and a position at 3o'clock), the disorder of the potential distribution near the substratecannot be completely corrected even though the voltage applied to theconductive ring is controlled according to the gap size between thesubstrate edge and the substrate holder.

In addition, when carrying the substrate in order to be installed on thesubstrate holder, it is likely to contact the substrate to theconductive ring if it is determined that the carrying fails. In thiscase, it is likely to cause the defects on the electronic devices bydamaging the substrate or generating particles by the contacting to beattached to the substrate.

In addition, it is difficult to cope with the inspection of the samplehaving different sizes in the inspection apparatus described in PatentDocument 1. The semiconductor wafer is processed in the manufacturingline of the semiconductor device and inspects it as a sample. However,there may be a case of inspecting a wafer having different sample sizesuch as a diameter of 200 mm (hereinafter, referred to as φ200), adiameter of 300 mm (hereinafter, referred to as φ300) or a largediameter of 450 mm (hereinafter, referred to as φ450).

In this case, in the apparatus described in Patent Document 1, since thesurface of the conductive ring installed at the outside of the sample isformed at the same height as the surface of the sample, i.e., thesubstrate, it is difficult to cope with the inspection of the samplehaving different diameters. For example, when the wafer of φ450 is puton the sample stage installed with the conductive ring for the wafer ofφ300, the wafer of φ450 is interfered with the conductive ring such thatit cannot be put on the sample stage, since the surface of theconductive ring is the same height as the wafer of φ300. In this case,in the apparatus described in Patent Document 1, there is a need topreviously prepare two kinds of conductive rings suitable for eachsemiconductor wafer and exchange them with each other. For example, whenthe wafer, i.e. the sample of φ450 is measured after inspecting thewafer of φ300, there is a problem in that the sample carrying mechanismof the inspection apparatus is complicated since the conductive ring forthe wafer of φ300 to the conductive ring for the wafer of φ450 areinstalled to be exchanged with each other.

An object of the present invention is to provide a semiconductorinspecting apparatus capable of preventing a position deviationoccurring at an outer peripheral portion thereof when inspecting anouter peripheral portion of a semiconductor wafer sample.

Means for Solving the Problems

To achieve the above objects, the present invention provides asemiconductor inspecting apparatus including a sample stage having asample is held thereon, a unit moving the sample stage, a beam sourceirradiating a charged particle beam to the surface of the sample, a beamscanning unit scanning the charged particle beam to the surface of thesample, the apparatus including: a first electrode at an outside fromthe outer edge of the sample having a first size and an inside from theouter edge of the sample having a second size and at a position lowerthan the bottom surface of the sample wherein the sample stage holds thesample in a first size and the sample in a second size larger than thefirst size; a second electrode at an outside from the outer edge of thesample having a second size; a first voltage supply source applyingvoltage to a first electrode or the second electrode; an analyzeranalyzing the voltage of the voltage supply source according to aninspecting position of the sample, a thickness of the sample and anirradiating condition of the charged particle beam, and a controllercontrolling the voltage of the voltage supply source based on ananalysis result of the analyzer.

Preferably, the present invention provides a semiconductor inspectingapparatus, wherein the sample stage holds the sample in a first size andthe sample in a second size larger than the first size and a surface ofthe sample stage is made of dielectric, the apparatus including: a firstelectrode installed within the dielectric and at an inside from theouter edge of the sample in a first size; a second electrode installedwithin the dielectric and at an outside of the first electrode andhaving an inner edge installed at an inside from an outer edge of thesample in a first size and an outer edge installed at an outside fromthe outer edge of the sample in a first size; a third electrodeinstalled within the dielectric, at an outside of the second electrodeand at an inside from an outer edge of the sample in a second size; afourth electrode installed within the dielectric and at an outside ofthe third electrode and having an inner edge installed at an inside fromthe outer edge of the sample in a second size and an outer edgeinstalled at an outside from the outer edge of the sample in a secondsize; a first voltage supply source installed in order to apply apositive voltage to the first electrode; a second voltage supply sourceinstalled in order to apply a negative voltage to the second electrode;a third voltage supply source installed in order to apply a positivevoltage to the third electrode; a fourth voltage supply source installedin order to apply a negative voltage to the fourth electrode; the secondelectrode attracting the sample in a first size or the sample in asecond size to the sample stage and serving as the first potentialcorrecting electrode, the fourth electrode attracting the sample in asecond size to the sample stage and serving as the second potentialcorrecting electrode, the analyzer analyzing voltage of the secondvoltage supply source or the fourth voltage supply source and thecontroller controlling the voltage of the second voltage supply sourceor the fourth voltage supply source based on an analysis result of theanalyzer.

More preferably, the present invention provides a semiconductorinspecting apparatus further including: an objective lens converging thecharged particle beam on the sample and a shield electrode installedbetween the objective lens and the sample, having a hole on an opticalaxis of the charged particle beam, and maintained at equipotential tothe sample, wherein a sum of at least one of a difference in a radiallength between an outer edge of the second electrode and an outer edgeof the sample in a first size and a difference in a radial lengthbetween an outer edge of the fourth electrode and an outer edge of thesample in a second size and a distance between a measurement position inmeasuring the outermost portion among measurement positions of thesample and the outer edge of the sample is equal to or larger than aradius of the hole of the shield electrode.

To achieve the above objects, the present invention provides ansemiconductor inspecting apparatus including: a third electrodeinstalled in a dielectric and at an inside from an outer edge of asample having a first size for attracting the sample having a first sizeor a sample having a second size into a sample stage by applying voltageto the surface of the sample stage made of dielectric; a fourthelectrode installed in a dielectric and at an inside from the outer edgeof the sample having a first size and at an outside of the thirdelectrode for attracting the sample having a first size or a samplehaving a second size into a sample stage by applying voltage to thesample stage, a fifth electrode in a dielectric and at an outside fromthe an outer edge of the sample having a first size and at an insidefrom the outer edge of the sample having a second size for attractingthe sample having a second size into a sample stage by applying voltageto the fourth electrode, a sixth electrode in a dielectric and at anoutside from the fifth electrode and at the inside from the outer edgeof the sample having a second size for attracting the sample having asecond size into a sample stage by applying voltage to the fifthelectrode; and a sixth electrode in a dielectric and at an outside fromthe fifth electrode and at an inside from the outer edge of the samplehaving a second size for attracting the sample having a second size intoa sample stage by applying voltage to the fifth electrode, a secondvoltage supply source installed to apply voltage at least one of thethird electrode and the fifth electrode, and a third voltage supplysource applying voltage having polarity different from the secondvoltage supply source to any one of the fourth electrode and the sixthelectrode.

Effects of the Invention

As set for the above, the present invention can provide a semiconductorinspecting apparatus capable of preventing a position deviationoccurring when inspecting an outer peripheral portion of a sample.Further, the present invention can provide application apparatuses suchas an electronic drawing apparatus, etc., capable of preventing theposition deviation occurring when patterns are drawn at the outerperipheral portion of the sample.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view showing a structure of a CD-SEMused in a first embodiment.

FIG. 2 is a side cross-sectional view showing a structure of a samplestage of a CD-SEM used in the first embodiment.

FIG. 3 is a diagram showing a sample stage of a CD-SEM used in the firstembodiment and is a cross-sectional view taken along line A-A of FIG. 2.

FIG. 4 is an enlarged side cross-sectional view of an objective lens, ashield electrode, and a vicinity of a CD-SEM and a sample stage used inthe first embodiment.

FIG. 5 is a diagram showing a relationship between a potential of a DCpower supply applied to a potential correcting electrode of a samplestage used in the CD-SEM used in the first embodiment and a bendingamount of primary electron and a relationship between voltage of a DCpower supply applied to a potential correcting electrode of a samplestage and a distance between an optical axis and an outer edge of asample.

FIG. 6 is a side cross-sectional view showing a structure of a samplestage of a CD-SEM used in a second embodiment.

FIG. 7 is a diagram showing a sample stage of a CD-SEM used in thesecond embodiment and is a cross-sectional view taken along line B-B ofFIG. 6.

FIG. 8 is an enlarged side cross-sectional view of an objective lens anda shield electrode of a CD-SEM and a vicinity of a sample stage used inthe second embodiment.

FIG. 9 is a side cross-sectional view showing a structure of a samplestage of a CD-SEM used in a third embodiment.

FIG. 10 is a side cross-sectional view showing a structure of a samplestage of a CD-SEM used in a fourth embodiment.

FIG. 11 is a side cross-sectional view showing a structure of a samplestage of a CD-SEM used in a fifth embodiment.

FIG. 12 is a side cross-sectional view showing a structure of a samplestage of a CD-SEM used in a sixth embodiment.

FIG. 13 is an enlarged side cross-sectional view of an objective lensand a shield electrode of a CD-SEM and a vicinity of a sample stage usedin the sixth embodiment.

FIG. 14 is a side cross-sectional view showing an example of a structureof a CD-SEM according to the related art.

FIG. 15 is an enlarged side cross-sectional view of an objective lensand a shield electrode of a CD-SEM and a vicinity of a sample stageshown in FIG. 14.

FIG. 16 is a side cross-sectional view showing a structure of a samplestage of a CD-SEM used in a seventh embodiment.

FIG. 17 is two graphs showing a relation among an amount that anelectrode in the sample stage of the CD-SEM used in the seventhembodiment is protruded from the outer edge of the sample, a observationposition of a sample, a hole radius of a shield electrode, and a bendingamount of a primary electron beam.

FIG. 18 is a side cross-sectional view showing a structure of the samplestage of the CD-SEM used in the seventh embodiment.

FIG. 19 is a side cross-sectional view showing a structure of a samplestage of a CD-SEM used in an eighth embodiment.

FIG. 20 is a diagram showing a sample stage of a CD-SEM used in theeighth embodiment and is a cross-sectional view taken along line C-C ofFIG. 19.

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described with reference tobest embodiments.

First Embodiment

Hereinafter, a first embodiment is an example of a semiconductorinspection apparatus using a charged particle beam applied to thepresent invention and a first embodiment applied to a CD-SEM will bedescribed in detail with reference to FIGS. 1 to 5.

FIG. 1 is a schematic diagram of an electron optical system of a CD-SEM.In addition, FIG. 2 is an enlarged diagram of a vicinity of a samplestage 11 used in a CD-SEM of the present embodiment. Among others, FIG.2(A) shows a structure when a wafer of φ300 as a sample 10 is installedon the sample stage 11. In addition, FIG. 3 is a diagram showing a crosssection of line A-A of the sample stage 11 used in the presentembodiment of FIG. 2. Further, in order to easily facilitate theposition relationship, an inner edge of a groove 50, an outer edge ofthe groove 50, and an inner edge of a concave portion 54 are shown by adotted line. Further, FIG. 4 shows a structure of a vicinity of a samplestage 11, a shield electrode 16, and an objective lens 9 when a wafer ofφ450 as the sample 10 is installed on the sample stage 11, inparticular, structure when a position of 2 mm from the outer edge of thesample 10 is inspected.

Further, when the plural samples 10 having different sizes are handled,the description thereof will be sequentially described below from asample having a small diameter to a sample having first and second sizeddiameters. In addition, plural electrodes in the sample stage and apower supply applying voltage thereto will be described on the whole oreach function thereof will be described in principle. In the firstembodiment, the sample 10 having the first size is a wafer of φ300 andthe sample 10 having a second size is a wafer of φ450.

As shown in FIG. 1, a primary electron beam 22 from an electron gun 1 bya voltage from an extraction electrode 2 is converged and deflected bypassing through a condenser lens 3, a scanning deflector 5, an aperture6, an objective lens 9, or the like, and is then irradiated at aninspecting position of the sample 10 installed on the sample stage 11.When the inspection position is changed, the sample 10 moves by using anX-Y stage 15 installed below the sample stage 11. In addition, in thepresent embodiment, the sample 10 is a disc-shaped semiconductor wafer.

In addition, a shield electrode 16 applying a retarding potential andthe same potential is installed at the vicinity of the sample 10,thereby relieving the disorder of the potential distribution at thevicinity of the sample 10. Further, the objective lens 9, etc., isconfigured in an axial symmetry shape using an optical axis 18 (shown bya dashed line) as a central axis.

The sample 10 is applied with a deceleration voltage (hereinafter,referred to as a retarding voltage) slower than that of a retardingpower supply 26, in order to decelerate the primary electron beam 22. Asecond electron 24 is generated from the sample 10 by the irradiation ofthe primary electron beam 22 and moves upward.

An E cross B deflector 8 is installed to be adjacent to an electron gunside of the objective lens 9. The E cross B deflector 8 is a deflectorthat removes the amount deflected by electric field and magnetic fieldin the case of the primary electron beam 22 and deflects electrons bysuperimposing electric field and magnetic field in the case of thesecondary electron 24. The secondary electron 24 moving upward from thesample 10 is deflected by the E cross B deflector 8 and is then input toa secondary electron detector 14. The secondary electron detector 14converts the input secondary electron 24 into an electric signal, whichis in turn amplified by a preamplifier (not shown) to a luminancemodulating input for an inspection image signal, thereby obtaining animage data of an inspection region.

A potential correcting electrode 44-2 is formed at an outer region ofthe sample 10 on the sample stage 1 and is connected with a voltagevariable DC power supply 48. As described below, the voltage of the DCpower supply 48 is controlled according to the inspection position ofthe CD-SEM (a distance between the optical axis 18 and the outer edge ofthe sample 10). For this reason, an analyzer 27 obtains the distancebetween the optical axis 18 and the outer edge of the sample 10 from acoordinate of an X-Y stage 15 and obtains a setting voltage of the DCpower supply 48 according to the distance and the irradiation conditionof the primary electron beam 22 and the controller 29 controls the DCpower supply 48 as the setting voltage thereof.

As shown in FIG. 2, the bottom surface (reverse side surface) of thesample 10 is pressed by a spring (not shown) to contact a contact pin 40of a conductor. The contact pin 40 is connected to the retarding powersupply 26 via a switch 42. In addition, the switch 42 is also connectedto the conductive sample stage 11 and the switch 42 is turned-on toapply the retarding voltage (negative voltage) to the sample 10 and thesample stage 11. Further, the sample stage 11 of the outer region of thesample 10 is provided with a ring-shaped groove 50 and the bottomsurface thereof is disposed at a position lower than the bottom surfaceof the sample 10. The bottom surface of the groove 50 is provided withan insulator 52-1 and the ring-shaped potential correcting electrode44-1 is installed thereon. The potential correcting electrode 44-1 isconnected with the voltage variable DC power supply 48 via a switch 46-1and applies a negative voltage to the potential correcting electrode44-1 by turning-on the switch 46-1. In this case, the retarding powersupply 26 and the DC power supply 48 are connected to the potentialcorrecting electrode 44-1 in series. Further, since the potentialcorrecting electrode 44-1 and the sample stage 11 are electricallyinsulated from each other by the insulator 52-1, the potentialcorrecting electrode 44-1 may be maintained at a potential (a negativepotential having a large absolute value) lower than that of the sample10. As a result, an equipotential surface 20-2 is elevated at theoutside of the sample 10. In addition, when the sample 10 is a sample 10having a first size, i.e., the wafer of φ300, since there is no need toapply voltage to the potential correcting electrode 44-2, it ispreferable to turn-off the switch 46-2 connected thereto. Further, ascan be clearly appreciated from FIG. 3, the ring-shaped electrodecorrecting electrodes 44-1 and 44-2 preferably have an approximateconcentric shape with respect to the circular sample 10 and sample stage11.

Next, when the sample 10 having a second size, i.e., a wafer of φ450 asthe sample 10 is disposed on the sample stage 11, a structure of thevicinity of the sample stage 11 is shown in FIG. 2(B). The sample stage11 disposed at the outer region of the sample 10 is disposed at a lowerposition than the bottom surface of the sample 10 and is provided with aconcave part 54. The concave part 54 is provided with an insulator 52-2and the ring-shaped potential correcting electrode 44-2 is installedthereon. The potential correcting electrode 44-2 is connected with thevoltage variable DC power supply 48 via a switch 46-2 and applies anegative voltage to the potential correcting electrode 44-2 byturning-on the switch 46-2. In this case, the retarding power supply 26and the DC power supply 48 are connected to the potential correctingelectrode 44-2 in series. Further, since the potential correctingelectrode 44-2 and the sample stage 11 are electrically insulated fromeach other by the insulator 52-2, the potential correcting electrode44-2 may be maintained at a potential (a negative potential having alarge absolute value) lower than that of the sample 10. As a result, anequipotential surface 20-2 is elevated at the outside of the sample 10.In addition, when the sample 10 is a sample 10 having a second size,i.e., the wafer of φ450, since there is no need to apply voltage to thepotential correcting electrode 44-1, it is preferable to turn-off theswitch 46-1 connected thereto.

Next, as shown in FIG. 4, when the potential of the potential correctingelectrode 44-2 is maintained to be lower than the potential of thesample 10, an equipotential surface 20-2 is elevated at the outside ofthe sample 10 by the potential difference between the sample 10 and thepotential correcting electrode 44-2. When the above-mentioned action isnot performed, as shown in FIG. 15, the equipotential surface 20-1 fallsat the outside of the sample 10 but according to a first embodiment, asshown in FIG. 4, the equipotential surface 20-2 is elevated such thatthe equipotential surface 20-1 is lifted upward. As a result, theequipotential surface 20-1 of the vicinity of the surface of the sample10 has the axial symmetry distribution based on the optical axis 18 as acenter. Therefore, even when the outer peripheral portion of the sample10 is inspected, the equipotential surface 20-1 of the vicinity of thesurface of the sample 10 has the axial symmetry distribution based onthe optical axis as a center and the bending of the primary electronbeam 22 is removed to prevent the position deviation.

In addition, FIG. 4 shows the case where the sample 10 is the sample 10having a second size, i.e., the wafer of φ450, but as shown in FIG.2(A), even in the case where the sample 10 is the sample 10 having thefirst size, i.e., the wafer of φ300, the potential of the potentialcorrecting electrode 44-1 similarly becomes the potential (a negativepotential having a larger absolute value) lower than that of the sample10 to elevate the equipotential surface 20-2, such that theequipotential surface 20-1 at the outside of the sample 10 is liftedupward. As a result, the equipotential surface 20-1 has the axialsymmetry distribution using the optical axis 18 as a center. Therefore,even when the outer peripheral portion of the sample 10 is inspected,the bending of the primary electron beam 22 is removed, therebypreventing the position deviation.

In addition, since the sample 10 is applied with the retarding voltagevia the contact pin 40, the sample 10 is maintained at the retardingpotential without having an effect on the potential of the potentialcorrecting electrode 44-1 or the potential correcting electrode 44-2. Inaddition, the contact pin 40 is installed at the position capable ofcontacting the smallest sample (in the first embodiment, a diameter ofthe first size, i.e., 300 mm) among the used samples 10, such that itmay also correspond to the sample 10 having different sizes.

In addition, in order to elevate the equipotential 20-2 by applying anegative voltage to the potential correcting electrode 44-1 and thepotential correcting electrode 44-2, it is necessary to make thepotential of each of the potential correcting electrode into thepotential of the sample 10, that is, a potential (a negative potentialhaving large absolute value) lower than the retarding potential. Forthis reason, it is necessary to install each of the potential correctingelectrode and the sample 10 at the position where they do not contacteach other. In addition, if the carrying of the sample fails when thesample 10 is installed on the sample stage 11, it is preferable that thesample 10 does not contact the potential correcting electrode 44-2. Forthis reason, in the first embodiment, the groove 50 and the concave part54 are formed at the position near the outside of the sample 10 on thesurface of the sample stage 11 and each of the potential correctingelectrode 44-1 and the potential correcting electrode 44-2 is formedthereat, such that each of the potential correcting electrode isdisposed below the bottom surface of the sample 10. Therefore, even whenthe sample 10 is installed on the sample stage 11 having differentsizes, if the carrying of the sample 10 fails when the sample 10 isinstalled on the sample stage 11, there is no risk of interfering thesample 10 with each of the potential correcting electrode, such that thepotential of each of the potential correcting electrode may beeffectively maintained at the potential lower than that of the sample10, i.e., the retarding potential.

According to the above-mentioned structure, even when the sample 10having different sizes is inspected, the bending of the primary electronbeam 22 is removed, thereby preventing the position deviation.

As shown in FIG. 15, the magnitude of falling the equipotential surface20-1 at the outside of the sample 10 when voltage is not applied to thepotential correcting electrode 44-1 or the potential correctingelectrode 44-2 is changed according to the inspection position of theCD-SEM, i.e., the distance between the optical axis 18 and the outeredge of the sample 10. In addition, a magnitude of increasing theequipotential surface 20-2 is changed according to the magnitude involtage applied to the potential correcting electrode 44-1 or thepotential correcting electrode 44-2 and the distribution of theequipotential surface 20-1 near the sample 10 is changed accordingly.For this reason, in order to remove the bending of the primary electronbeam 22, the optimal voltage applied to the potential correctingelectrode 44-1 or the potential correcting electrode 44-2 is changedaccording to the distance between the optical axis 18 and the outer edgeof the sample 10. In addition, the optimal voltage is changed by thestructure of the inspection apparatus, such as the structure of theobjective lens 9, etc., and the retarding potential, etc. In the CD-SEMaccording to the first embodiment, when the retarding voltage is −2500Vand the sample 10 having the first size, i.e., the wafer of φ300 isinspected, the inventors confirm through the experiment that therelationship between the voltage (the potential of the potentialcorrecting electrode 44-1 is a potential applying the retarding voltageto the voltage) of the DC power supply 48 and the bending amount of theprimary electron beam 22 is shown as the graph as shown in FIG. 5(A).Further, from the foregoing experiment, when the distance from the outeredge of the sample 10 to the inspection position (a position of theoptical axis 18) having the problem with the bending of the primaryelectron beam 22 is 1 to 4 mm, the voltage of the DC power supply 48,i.e., the optimal voltage in order to make the bending amount of theprimary electron beam 22 into zero can be appreciated from FIG. 5(B).The potential of the potential correcting electrode 44-1 is changed bypreviously obtaining the data and changing the voltage of the DC powersupply 48 according to the inspection position to change the potentialof the potential correcting electrode 44-1, thereby preventing thebending of the primary electron beam 22. As a result, even when theouter peripheral portion of the sample 10 is inspected, the positiondeviation may be removed.

Further, the case where the sample 10 having the first size, the waferof φ300 as the sample 10 is performed is described as an example andeven when the sample 10 having a second size, i.e., the wafer of φ450 isinspected, the bending of the primary electron beam 22 is prevented bythe same method, thereby making it possible to inspect the positiondeviation even in the case of the outer peripheral portion of the sample10. However, since the thickness of the wafer of φ450 and the wafer ofφ300 is different, the optimal voltage of the DC power supply 48 formaking the bending of the primary electron beam 22 into zero isdifferent. For this reason, even when the sample 10 is the sample 10 ofa second size, i.e., the wafer of φ450, there is a need to previouslyobtain data as shown in FIGS. 5A and 5B.

As described above, the data of the voltage of the DC power supply 48controlled according to the distance between the optical axis 18 and theouter edge of the sample 10 is stored in the analyzer 27 shown inFIG. 1. The analyzer 27 obtains the distance between the optical axis 18and the outer edge of the sample 10 from the coordinate of the X-Y stage15 and obtains the setting voltage of the DC power supply 48 accordingto the distance, the thickness of the sample 10, and the irradiationconditions of the primary electron beam 22 such as the retardingvoltage, etc., and the controller 29 controls the voltage of the DCpower supply 48 as the setting voltage thereof. Therefore, the firstembodiment controls the potential of the potential correcting electrode44-1 and the potential correcting electrode 44-2 to prevent the bendingof the primary electron beam 22, thereby making it possible to removethe position deviation even in the case of inspecting the outerperipheral portion of the sample 10.

Second Embodiment

Next, a second embodiment of the present invention will be describedwith respect to only portions different from the first embodiment.Although the first exemplary of the present invention installs thesample 10 on the sample stage 11, it does not attract the sample 10. Onthe other hand, the second embodiment uses the electrostatic chuck asthe sample stage 11 to attract the sample 10 into the sample stage 11and firmly hold the sample thereto. Hereinafter, the structure of thesecond embodiment will be described with reference to FIGS. 6 to 8.

FIGS. 6A and 6B each are a diagram showing a structure of the vicinityof the sample stage 11 when the sample 10 having a first size, i.e., thewafer of φ300 as the sample is installed on the sample stage 11 and whenthe sample 10 having a second size, i.e., the wafer of φ450 as thesample is installed on the sample stage 11, respectively. In addition,FIG. 7 is a top view showing a cross-sectional view taken along line B-Bof the sample stage 11 shown in FIG. 6(A). Further, in order to easilyappreciate the positional relationship, the inner edge and the outeredge of the groove 50, the inner edge and the outer edge of thepotential correcting electrode 44-1, the inner edge of the concaveportion 54, and the inner edge and the outer edge of the potentialcorrecting electrode 44-2 are shown by a dotted line. In addition, FIG.8 is a diagram showing a structure of the vicinity of the sample stage11, the shield electrode 16, and the objective lens 9 when the sample 10of a second size, i.e., the wafer of φ450 as the sample is installed onthe sample stage 11.

As shown in FIG. 6, the sample stage 11 used in the second embodiment isconfigured to include a dielectric part 34 of ceramic and a metal base35, attracting electrodes 32-1 to 32-4 installed in the dielectric part34, and the potential correcting electrodes 44-1 to 44-2 formed on thesurface of the dielectric part 34. In addition, the outer edge of theelectrode 32-2 is configured to have a diameter equal to or smaller thanthe outer edge of the sample 10 having a first size, i.e., the wafer ofφ300 as the sample 10. Similarly, the outer edge of the electrode 32-4is configured to have a diameter equal to or smaller than the outer edgeof the sample 10 having a second size, i.e., the wafer of φ450 as thesample 10.

As shown in FIG. 6(A), when the sample 10 having a first size, i.e., thewafer of φ300 as the sample 10 is installed on the sample stage 11, theelectrode 32-1 and the electrode 32-2 are each connected to the DC powersupply 38-1 and the DC power supply 38-2 via the switches 36-1 and 36-2and these switches are turned-on to apply the positive and negativevoltage to the electrode 32-1 and the electrode 32-2, respectively. Thebottom surface (rear surface) of the sample 10 is provided with thecontact pin 40 pressed by the spring (not shown) and connected to theretarding power supply 26 via the switch 42 and is applied with theretarding voltage by turning-on the switch 42. In addition, since the DCpower supply 38-1 applying the negative voltage and the DC power supply38-2 applying the positive voltage are also connected with the retardingpower supply 26 in series, the positive and negative voltage based onthe retarding potential is applied to the electrode 32-1 and theelectrode 32-2, respectively. Consequently, a coulomb force orJonhson-Rahbeck force are generated to effectively attract the sample 10to the surface of the sample stage 11. In addition, the attractingsurface to attract the sample 10 on the surface of the sample stage 11is configures to planarize the sample 10 when the sample 10 isattracted. In addition, the electrode 32-1 and the electrode 32-2 areconfigured to cover approximately the whole region of the sample 10 togenerate the adsorption force to the sample stage 11 over the wholeregion of the sample 10, such that even the bent sample 10 is attractedto be planarized.

The surface of the dielectric part 34 of the outer region of the sample10 is provided with a ring-shaped groove 50 and the bottom surfacethereof is disposed at a position lower than the bottom surface of thesample 10. In addition, the bottom surface of the groove 50 is coatedwith a conductive film (for example, a metal film), such that thering-shaped potential correcting electrode 44-1 is formed. Thering-shaped potential correcting electrode 44-1 is connected with thevoltage variable DC power supply 48 via the switch 46-1 and the switch46-1 is turned-on to apply the negative voltage to the potentialcorrecting electrode 44-1, such that the equipotential surface 20-2 iselevated at the outside of the sample. Therefore, similar to the firstembodiment, even when the outer peripheral portion of the sample 10 isinspected, the equipotential surface 20-1 (not shown) of the vicinity ofthe surface of the sample 10 has the axial symmetry distribution basedon the optical axis as a center and the bending of the primary electronbeam 22 is removed to prevent the position deviation. In addition, whenthe sample 10 is a sample 10 having a first size, i.e., the wafer ofφ300, since there is no need to apply voltage to the electrode 32-3, theelectrode 32-4, and the potential correcting electrode 44-2, it ispreferable to turn-off the switch 36-3, the switch 36-4, and the switch46-2 connected thereto.

Next, when the sample 10 having a second size, i.e., a wafer of φ450 asthe sample 10 is disposed on the sample stage 11, a structure of thevicinity of the sample stage 11 is shown in FIG. 6(B). In this case,similar to the use of the sample 10 having a first size, i.e., the waferof φ300 shown in FIG. 6(A), voltage is applied to the electrode 32-1 andthe electrode 32-2 as well as voltage is also applied to the electrode32-3 and the electrode 32-4. These electrode 32-3 and electrode 32-4 arealso connected with the DC power supply 38-1 and the DC power supply38-2, respectively, via the switch 36-3 and the switch 36-4. For thisreason, these switches 36-1 to 36-4 are turned-on, such that the sample10 is attracted into the sample stage 11. In this case, the electrode32-1 to 32-4 are configured to cover approximately the whole region ofthe sample 10 to generate the adsorption force to the sample stage 11over the whole region of the sample 10, such that even the bent sample10 is attracted to be planarized.

The dielectric part 34 disposed at the outer region of the sample 10 isconcavely disposed at a lower position than the bottom surface of thesample 10. The surface thereof is provided with the potential correctingelectrode 44-2 and the potential correcting electrode 44-2 is connectedto the DC power supply 48 via the switch 46-2. The switch 46-2 isturned-on to apply the negative voltage to the potential correctingelectrode 44-2 such that the equipotential surface 20-2 is elevated atthe outside of the sample 10. Therefore, as shown in FIG. 8, theequipotential surface 20-1 of the vicinity of the surface of the sample10 has an axial symmetry distribution based on the optical axis similarto the first exemplary embodiment and the bending of the primaryelectron beam 22 is removed, thereby preventing the position deviation.In addition, even when the sample 10 is the sample having a second size,i.e., the wafer of φ450, the potential correcting electrode 44-1 isformed at the bottom surface of the groove 50, such that the sample 10and the potential correcting electrode 44-1 are installed and attractedon the sample stage 11 without the sample 10 and the potentialcorrecting electrode 44-1 being interfering and contacting with eachother. In addition, when the sample 10 is a sample 10 having a secondsize, i.e., the wafer of φ450, since there is no need to apply voltageto the potential correcting electrode 44-1, it is preferable to turn-offthe switch 46-1.

In addition, since the sample 10 is applied with the retarding voltagevia the contact pin 40, the sample 10 is maintained at the retardingpotential without having an effect on the potential of the potentialcorrecting electrode 44 or the electrode 32-1 at the inside thereof orthe electrode 32-2 at the outside thereof. In addition, the contact pin40 is installed at the position capable of contacting the smallestsample (in the second embodiment, a diameter of the first size, i.e.,300 mm) among the used samples, such that it may also correspond to thesample 10 having different sizes. According to the above-mentionedstructure, even when the sample 10 having different sizes is inspected,the bending of the primary electron beam 22 is prevented in the case ofinspecting the outer peripheral portion, thereby making it possible toprevent the position deviation.

In addition, as described above, when the contact pin 40 is pressed onthe sample 10 by the spring but the sample 10 is not attracted into thesample stage 11, the sample 10 is pushed up by the contact pin 40 suchthat it is floated from the sample stage 11 or the region pressed by thecontact pin 40 of the sample 10 may be convexly bent. When there is aneed to measure the precision of a nanometer level such as the CD-SEMused in the embodiment, the degradation in the measurement precision iscaused, which is not preferable. On the other hand, since the secondembodiment uses the electrostatic chuck as the sample stage 11 to firmlyattract the sample 10 into the sample stage 11, the sample 10 is liftedup by the contact pin 40, such that there is no risk that it may befloated from the sample stage 11 or the region pressed by the contactpin 40 of the sample 10 may be bent, thereby making it possible toprevent the degradation of the measurement precision.

In addition, when the electrostatic chuck is not used as the samplestage 11 as in the first embodiment, the height of the outer edge of thesample 10 is not uniform over the whole circumference of 360 degree inthe case of the bent sample 10. In this case, when the vicinity of theouter edge of the sample 10 is inspected, a scheme of falling theequipotential surface 20-1 of the vicinity of the outer edge of thesample is changed according to the position of the circumferencedirection. In this case, the optimal voltage of the DC power supply 48is changed according to the position of the circumference direction ofthe inspecting position in addition to the distance between the opticalaxis 18 and the outer edge of the sample 10 and the irradiationconditions of the primary electron beam 22, such that the control of theDC power supply 48 is complicated. On the other hand, the secondembodiment uses the electrostatic chuck as the sample stage 11, thesample 10 is attracted on the whole surface of the sample stage 11 toremove the bending of the sample 10, such that the height at the outeredge of the sample 10 is uniform over the entire circumference of 360degree. For this reason, the factors of determining the optimal voltageof the DC power supply 48 are only the distance between the optical axis18 and the outer edge of the sample 10, the thickness of the sample 10,and the irradiation conditions of the primary electron beam 22, suchthat it is easy to control the DC power supply 48.

In addition, the potential correcting electrode (in the secondembodiment, the potential correcting electrode 44-1) used when the smallsample 10 (in the second embodiment, a wafer having a first size, i.e.,φ300) is inspected is not necessarily disposed at a position lower thanthe bottom surface of the sample 10, but the potential correctingelectrode (in the second embodiment, the potential correcting electrode44-2) used when the largest sample 10 (in the second embodiment, a waferhaving a second size, i.e., φ450) is observed is not limited thereto.Therefore, the potential correcting electrode may be installed atposition higher than the bottom surface of the sample 10 if the positionis a position where the sample 10 and the potential correcting electrodedo not contact each other. However, if the carrying of the sample failswhen the sample 10 is installed on the sample stage 11, there is a riskof contacting the potential correcting electrode 44-2 to the sample 10in the structure where the potential correcting electrode 44-2 is at theposition higher than the bottom surface of the sample 10. In this case,the particle generated by the contact may be attached to the sample 10,which becomes a cause of degrading the manufacturing yield of thesemiconductor. For this reason, when the largest sample 10 is observed,it is preferable that the used potential correcting electrode 44-2 isinstalled at a position lower than the bottom surface of the sample 10.

In addition, as in the second embodiment, when the electrostatic chuckis used as the sample stage 11, it is important to remove the residualadsorption of the sample 10 into the sample stage 11 by turning-off theswitches 36-1 to 36-4 after the measurement processing is performed. Tothis end, it is preferable that the areas of the positive and negativeelectrodes are the same. In the second embodiment, it is preferable thatthe areas of the electrode 32-1 and the electrode 32-2 are the same, andthat the areas of the electrode 32-3 and the electrode 32-4 are thesame.

In addition, as can be clearly appreciated from FIG. 7, similarly to thering-shaped potential correcting electrodes 44-1 and 44-2, it ispreferable that each electrode 32-2, 32-3, and 32-4 is formed in aconcentric shape approximately similar to a circular electrode 32-1.

Further, although the second embodiment shows ceramic as the dielectricmaterial of the dielectric part 34, alumina or SIC, etc., is used. Inaddition, the dielectric material in addition to ceramic, etc., such aspolyimide, or the like, may be also used.

As described above, similar to the first embodiment, the analyzer 27obtains the distance between the optical axis 18 and the outer edge ofthe sample 10 from a coordinate of an X-Y stage 15 and obtains thesetting voltage of the DC power supply 48 according to the distance andthe irradiation condition of the primary electron beam 22 such as theretarding voltage, etc., by applying the shown sample stage 11 to theCD-SEM shown in FIG. 1 and the controller 29 controls the DC powersupply 48 as the setting voltage thereof. Therefore, the bending of theprimary electron beam 22 is prevented by controlling the potential ofthe electrode 32-3 or the potential correcting electrode 44-2, therebyobtaining the effect of removing the position deviation even in the caseof inspecting the outer peripheral portion of the sample 10. Further,since the second embodiment uses the electrostatic chuck as the samplestage 11 to firmly attract the sample 10 into the sample stage 11, thesample 10 is lifted up by the contact pin 40, such that there is no riskthat it may be floated from the sample stage 11 or the region pressed bythe contact pin 40 of the sample 10 may be bent, thereby making itpossible to prevent the degradation of the measurement precision.

Third Embodiment

Next, a third embodiment of the present invention will be described withrespect to only portions different from the second embodiment. Thesecond embodiment forms the groove 50 or the concave part 54 on thesurface of the dielectric portion 34 of the sample stage 11 that is theelectrostatic chuck and the bottom surface thereof is provided with thepotential correcting electrode 44-1 and the potential correctingelectrode 44-2, respectively. In this case, in addition to the processof manufacturing the sample stage 11 having the general electrostaticchuck structure, the process of forming the groove 50 and the concavepart 54 in the dielectric portion 34 and the process of forming thepotential correcting electrode 44-1 and the potential correctingelectrode 44-2 are newly needed. Therefore, the third embodiment has arelatively simple structure. The third embodiment installs the potentialcorrecting electrode 44-1 and the potential correcting electrode 44-2 atthe position at the outside of the sample 10 or below the bottom surfaceof the sample 10 to implement a mechanism of preventing the bending ofthe primary electron beam even when inspecting the vicinity of the outeredge of the sample 10. Hereinafter, the third embodiment will bedescribed with reference to FIG. 9.

FIG. 9(A) is an enlarged view of a structure of the vicinity of thesample stage 11 when the sample 10 having a first size, i.e., the waferof φ300 as the sample 10 is installed on the sample stage 11.

The attracting electrodes 32-1 and 32-2 are each connected with the DCpower supply 38-1 and the DC power supply 38-2 via the switches 36-1 andthe switches 36-2 and turn-on these switches to attract the sample 10into the sample stage 11. The inside of the dielectric part 34 of theouter region of the sample 10 is provided with the ring-shaped potentialcorrecting electrode 44-1 and the voltage variable DC power supply 48 isconnected thereto via a switch 46-1 and the negative voltage is appliedto the potential correcting electrode 44-1 by turning-on the switch46-1. The potential correcting electrode 44-1 is covered with thedielectric part 34 made of the dielectric (in the present embodiment,ceramic) of the relative dielectric constant of about 8 to 10 and theequipotential surface 20-2 is elevated at the outside of the sample 10by the dielectric part 34. Therefore, similar to the first and secondembodiments, even when the outer peripheral portion of the sample 10 isinspected, the equipotential surface 20-1 (not shown) of the vicinity ofthe surface of the sample 10 has the axial symmetry distribution basedon the optical axis as a center and the bending of the primary electronbeam 22 is removed to prevent the position deviation. In addition, whenthe sample 10 is a sample 10 having a first size, i.e., the wafer ofφ300, since there is no need to apply voltage to the electrode 32-3, theelectrode 32-4, and the potential correcting electrode 44-2, it ispreferable to turn-off the switch 36-3, the switch 36-4, and the switch46-2 connected thereto.

Next, when the sample 10 having a second size, i.e., a wafer of φ450 asthe sample 10 is disposed on the sample stage 11, a structure of thevicinity of the sample stage 11 is shown in FIG. 9(B). In this case,similar to the use of the sample 10 having a first size, i.e., the waferof φ300 shown in FIG. 9(A), voltage is applied to the electrode 32-1 andthe electrode 32-2 as well as voltage is also applied to the attractingelectrode 32-3 and electrode 32-4. These electrode 32-3 and electrode32-4 are also connected with the DC power supply 38-1 and the DC powersupply 38-2, respectively, via the switch 36-3 and the switch 36-4. Forthis reason, these switches 36-1 to 36-4 are turned-on, such that thesample 10 is attracted into the sample stage 11. In this case, theattracting electrode 32-1 to 32-4 are configured to cover approximatelythe whole region of the sample 10 to generate the adsorption force tothe sample stage 11 over the whole region of the sample 10, such thateven the bent sample 10 is attracted to be planarized.

The inside of the dielectric part 34 of the outer region of the sample10 is provided with the potential correcting electrode 44-2 and thepotential correcting electrode 44-2 is connected to the DC power supply48 via the switch 46-2. The switch 46-2 is turned-on to apply thenegative voltage to the potential correcting electrode 44-2 such thatthe equipotential surface 20-2 is elevated at the outside of the sample10. Therefore, similar to the first embodiment, the equipotentialsurface 20-1 (not shown) of the vicinity of the surface of the sample 10has the axial symmetry distribution based on the optical axis as acenter and the bending of the primary electron beam 22 is removed toprevent the position deviation. In addition, when the sample 10 is thewafer of φ450, since there is no need to apply voltage to the potentialcorrecting electrode 44-1, it is preferable to turn-off the switch 46-1.

In addition, the potential correcting electrode 44-1 and the potentialcorrecting electrode 44-2 are disposed at a lower position than thebottom surface of the sample 10. Further, since they are covered withthe dielectric part 34, there is no risk of interfering or contactingwith the sample 10.

As described above, similar to the first embodiment, the analyzer 27obtains the distance between the optical axis 18 and the outer edge ofthe sample 10 from a coordinate of an X-Y stage 15 and obtains thesetting voltage of the DC power supply 48 according to the distance andthe irradiation condition of the primary electron beam 22 such as theretarding voltage, etc., by applying the shown sample stage 11 to theCD-SEM shown in FIG. 1 and the controller 29 controls the DC powersupply 48 as the setting voltage thereof. Therefore, the firstembodiment controls the potential of the potential correcting electrode44-1 or the potential correcting electrode 44-2 to prevent the bendingof the primary electron beam 22, thereby making it possible to removethe position deviation even in the case of inspecting the outerperipheral portion of the sample 10.

Further, the third embodiment uses the electrostatic chuck as the samplestage 11, the sample 10 is attracted on the whole surface of the samplestage 11 to remove the bending of the sample 10, such that the height atthe outer edge of the sample 10 is uniform over the entire circumferenceof 360 degree. As a result, as shown in the second embodiment, thefactors of determining the optimal voltage of the DC power supply 48 areonly the distance between the optical axis 18 and the outer edge of thesample 10, the thickness of the sample 10, and the irradiationconditions of the primary electron beam 22, such that it is easy tocontrol the DC power supply 48.

In addition, the third embodiment forms the potential correctingelectrode 44-1 and the potential correcting electrode 44-2 in thedielectric part 34 made of ceramic. The structure may be formed byprinting the shape of the electrodes 32-1 to 32-4 and the potentialcorrecting electrode 44-1 and the potential correcting electrode 44-2 onthe green sheet of the dielectric by a screen printing method usingpaste including a conductor (for example, tungsten), overlapping a greensheet having different dielectric therewith, stacking and integrating itby the heating pressure, and burning it. For this reason, similar to thestructure shown in the second embodiment, a complicated process offorming the groove 50 or the concave part 54 in the dielectric part 34and forming the potential correcting electrode 44-1 and the potentialcorrecting electrode 44-2 therein may be avoided, thereby making itpossible to manufacture the sample stage 11 at low cost.

Fourth Embodiment

Next, a fourth embodiment will be described. In the third embodiment,the two potential correcting electrode 44-1 and potential correctingelectrode 44-2 each used when two kinds of samples 10 having differentsizes are inspected are installed in the dielectric part 34 of thesample stage 11. On the other hand, in the fourth embodiment, theattracting electrode used to attract the large sample 10 into the samplestage 11 is used as the potential correcting electrode when the smallsample 10 is measured, such that it corresponds to the measurement ofthe sample 10 having a different size by a relatively simple structure.Hereinafter, the fourth embodiment will be described only portionsdifferent from the first to third embodiments with reference to FIG. 10.

FIG. 10(A) is an enlarged view of the structure of the vicinity of thesample stage 11 when the sample 10 having a first size, i.e., the waferof φ300 as the sample 10 is installed on the sample stage 11. Theelectrode 32-1 and the electrode 32-2 are each connected to the DC powersupply 38-1 and the DC power supply 38-2 via the switches 36-1 and 36-2and these switches are turned-on to attract the sample 10 into thesample stage 11.

The ring-shaped electrode 32-3 and 32-4 are formed in the dielectricpart 34 of the outer region of the sample 10 having a first size, i.e.,the wafer of φ300 and turns-on the switch 36-3 to allow the voltagevariable power supply 38-3 connected to the retarding power supply 26 inseries to apply voltage (a negative voltage having a large absolutevoltage) lower than the retarding voltage to the electrode 32-3, suchthat the equipotential surface 20-2 is elevated at the outside of thesample 10 through the dielectric part 34. Therefore, similar to thefirst to third embodiments, even when the outer peripheral portion ofthe sample 10 is inspected, the equipotential surface 20-1 (not shown)of the vicinity of the surface of the sample 10 has the axial symmetrydistribution based on the optical axis as a center and the bending ofthe primary electron beam 22 is removed to prevent the positiondeviation. Further, as described above, in order to prevent the bendingof the primary electron beam 22, since there is a need to controlvoltage applied to the electrode at the outside of the sample 10, thepower supply 38-3 is the voltage variable DC power supply.

In addition, as shown in FIG. 10(B), when the sample 10 is the sample 10having a second size, similar to the third embodiment, the wafer ofφ450, the switch 36-5 is turned-on to apply voltage (a negative voltagehaving a larger absolute voltage) lower than the retarding voltage tothe potential correcting electrode 44-2 installed at the outer region ofthe sample 10 of the dielectric part 34, such that the equipotentialsurface 20-2 is elevated. The equipotential surface 20-1 (not shown) atthe vicinity of the surface of the sample 10 is the axial symmetrydistribution based on the optical axis, such that the bending of theprimary electron beam 22 is removed, thereby preventing the positiondeviation. In addition, as described above, although the power supply38-3 is the voltage variable DC power supply, in order to remove theresidual adsorption of the sample 10 for the sample stage 11 afterturning-off the switches 38-1 to 38-5, it is preferable that theabsolute values in the voltage of the voltage variable DC power supply38-3 and the voltage variable DC power supply 38-4 are the same in anopposite polarity of plus and minus.

As described above, similar to the first to third embodiments, theanalyzer 27 obtains the distance between the optical axis 18 and theouter edge of the sample 10 from a coordinate of an X-Y stage 15 andobtains the setting voltage of the DC power supply 38-3 or the DC powersupply 38-5 according to the distance and the irradiation condition ofthe primary electron beam 22 such as the retarding voltage, etc., byapplying the shown sample stage 11 to the CD-SEM shown in FIG. 1 and thecontroller 29 controls the DC power supply 38-3 or the DC power supply38-5 as the setting voltage thereof. Therefore, the bending of theprimary electron beam 22 is prevented by controlling the potential ofthe electrode 32-3 or the potential correcting electrode 44-2, therebyobtaining the effect of removing the position deviation even in the caseof inspecting the outer peripheral portion of the sample 10. Inaddition, the electrode 32-3 used to attract the large sample 10 intothe sample stage 11 is used as the potential correcting electrode whenmeasuring the small sample 10, thereby making it possible to obtain theforegoing effects using the relatively simple structure.

Fifth Embodiment

Next, a fifth embodiment of the present invention will be described withrespect to only portions different from the first to fourth embodiments.In the third embodiment, the two potential correcting electrode 44-1 andpotential correcting electrode 44-2 each used when two kinds of samples10 having different sizes are inspected are installed in the dielectricpart 34 of the sample stage 11 that is the electrostatic chuck. On theother hand, in the fifth embodiment, the electrode used to attract thesample 10 into the sample stage 11 is further protruded than the outeredge of the sample 10, thereby making it possible to obtain the effectof preventing the position deviation when the outer peripheral portionof the sample 10 is inspected. Hereinafter, the fifth embodiment will bedescribed with reference to FIG. 11.

FIG. 11(A) is an enlarged view of a structure of the vicinity of thesample stage 11 when the sample 10 having a first size, i.e., the waferof φ300 as the sample 10 is installed on the sample stage 11. Theelectrodes 32-1 and 32-2 are each connected with the voltage variable DCpower supply 38-1 via the switches 36-1 and 36-2 the voltage variable DCpower supply 38-2 similar thereto and turn-on these switches to attractthe sample 10 into the sample stage 11. Although the third embodimentmakes the outer edge of the electrode 32-2 equal to or smaller than theouter edge of the sample 10 having a first size, i.e., the wafer ofφ300, the fifth embodiment forms the diameter of the outer edge of theelectrode 32-2 into a diameter of 306 mm to be larger by 3 mm than thesample 10 having a first size, i.e., the sample 10 that is the wafer ofφ300. In addition, the DC power supply 38-2 set as the negative voltageis connected with the retarding power supply 26 in series, such that theelectrode 32-2 is applied with voltage (negative voltage having a largerabsolute value) smaller than the retarding voltage. As a result, theequipotential surface 20-2 is elevated at the outside of the sample 10through the dielectric part 34 from the electrode 32-2 that is a portionprotruded from the sample 10. Therefore, the equipotential surface 20-1(not shown) of the vicinity of the surface of the sample 10 has theaxial symmetry distribution based on the optical axis as a center andthe bending of the primary electron beam 22 is removed to prevent theposition deviation. In addition, the voltage variable DC power supply38-2 is set to be voltage suitable for removing the bending of theprimary electron beam 22 Further, it is preferable that the voltagevariable DC power supply 38-1 is set to be a suitable voltage in orderto remove the residual adsorption of the sample 10 for the sample stage11 after the switch 38-1 and the switch 38-2 are turned-off. Inaddition, when the sample 10 is the sample 10 having a first size, i.e.,the wafer of φ300, since there is no need to apply voltage to theelectrode 32-3 and the electrode 32-4, it is preferable to turn-off theswitch 38-3 and the switch 38-4.

Next, FIG. 11(B) is an enlarged view of the structure of the vicinity ofthe sample stage 11 when the sample 10 having a second size, i.e., thewafer of φ450 as the sample 10 is disposed on the sample stage 11. Inthis case, voltage is applied to the electrode 32-1 and the electrode32-2 and voltage is also applied to the electrode 32-3 and the electrode32-4. These electrodes are connected with the voltage variable DC powersupply 38-3 and the voltage variable DC power supply 38-4 via the switch36-3 and the switch 36-4 and turn-on the switch 36-3 and the switch 36-4to attract the sample 10 into the sample stage 11.

Although the third embodiment makes the outer edge of the electrode 32-4equal to or smaller than the outer edge of the sample 10 having a secondsize, i.e., the wafer of φ450, the fifth embodiment forms the diameterof the outer edge of the electrode 32-4 into a diameter of 456 mm to belarger by 3 mm than the sample 10 that is the wafer of φ450. Inaddition, the DC power supply 38-4 set as the negative voltage isconnected with the retarding power supply 26 in series, such that theelectrode 32-4 is applied with voltage (negative voltage having a largerabsolute value) smaller than the retarding voltage. As a result, theequipotential surface 20-2 is elevated at the outside of the sample 10through the dielectric part 34 from the electrode 32-4 that is a portionprotruded from the sample 10. Therefore, the equipotential surface 20-1(not shown) of the vicinity of the surface of the sample 10 has theaxial symmetry distribution based on the optical axis as a center andthe bending of the primary electron beam 22 is removed to prevent theposition deviation. In addition, the voltage variable DC power supply38-4 is set to be voltage suitable for removing the bending of theprimary electron beam 22. Further, it is preferable that other voltagevariable DC power supplies 38-1 to 38-3 are set to be a suitable voltagein order to remove the residual adsorption of the sample 10 for thesample stage 11 after the switches 38-1 to 38-4 are turned-off.

By applying the above-mentioned sample stage 11 to the CD-SEM shown inFIG. 1, similar to the first to fourth embodiments, the analyzer 27obtains the distance between the optical axis 18 and the outer edge ofthe sample 10 from a coordinate of an X-Y stage 15 and obtains thesetting voltage of the DC power supply 38-2 or the DC power supply 38-4according to the distance, the thickness of the sample 10, and theirradiation condition of the primary electron beam 22 such as theretarding voltage sample stage. The controller 29 controls the DC powersupply 38-2 or the DC power supply 38-4 base on the setting voltagethereof. Therefore, the potential of the electrode 32-2 or electrode32-4 is controlled and the bending of the primary electron beam 22 isprevented, thereby obtaining the effect of removing the positiondeviation even in the case of inspecting the outer peripheral portion ofthe sample 10.

In addition, the fifth embodiment uses the electrode for attracting thesample 10 into the sample stage 11 in order to prevent the bending ofthe primary electron beam 22 such that there is no need to install a newpotential correcting electrode, thereby making it possible to obtain theforegoing effects using the relatively simple structure.

In addition, since the electrodes 44-1 to 44-4 are at a position lowerthan the bottom surface of the sample 10 and is covered with thedielectric part 34, there is no risk of interfering or contacting withthe sample 10. As a result, the fifth embodiment can obtain an effect ofpreventing the position deviation when inspecting the outer peripheralportion while effectively installing and attracting the sample 10 on thesample stage 11.

Sixth Embodiment

Next, a sixth embodiment of the present invention will be described withrespect to only portions different from the first to fifth embodiments.The third embodiment installs the potential correcting electrodes eachused, when two kinds of samples 10 having different sizes are inspected,in the dielectric part 34 of the electrostatic chuck, i.e., the samplestage 11. On the other hand, the sixth embodiment installs the pluralconcentric potential correcting electrodes corresponding to two kinds ofsamples 10 having different sizes at the outside of the sample 10,thereby making it possible to densely control the distribution of theequipotential surface 20-2 on the potential correcting electrode 44.

FIGS. 12(A) and 12(B) each are a diagram showing a configuration of thevicinity of the sample stage 11 when the sample 10 having a first size,i.e., the wafer of φ300 as the sample 10 is installed on the samplestage 11 and when the sample 10 having a second size, i.e., the wafer ofφ450 as the sample 10 is installed on the sample stage 11, respectively.In addition, FIG. 13 is a diagram showing a configuration of thevicinity of the sample stage 11, the shield electrode 16, and theobjective lens 9 when the sample 10 of a second size, i.e., the wafer ofφ450 as the sample 10 is installed on the sample stage 11.

As shown in FIG. 12(A), the electrodes 32-1 and 32-2 are each connectedwith the voltage variable DC power supply 38-1 via the switches 36-1 andthe voltage variable DC power supply 38-2 similar thereto and turn-onthese switches to attract the sample 10 into the sample stage 11. In thethird embodiment, one ring-shaped potential correcting electrode 44-1 isinstalled in the dielectric part 34 and at the outside of the electrode32-2, while in the sixth embodiment, the ring-shaped potentialcorrecting electrode 44-1 a is installed at the outside of the electrode32-2 and the ring-shaped potential correcting electrode 44-1 b isinstalled at the outside thereof. In addition, the potential correctingelectrode 44-1 a and the potential correcting electrode 44-1 b areconnected with the voltage variable DC power supply 48 a and the voltagevariable DC power supply 48 b via the switch 46-1 a and the switch 46-1b and turn-on these switches to apply the negative voltage to thepotential correcting electrode 44-1 a and the potential correctingelectrode 44-1 b. In addition, the DC power supply 48 a and the DC powersupply 48 b are connected to the retarding power supply 26 in series,such that they are maintained at a potential (negative potential havinga larger absolute value) lower than the sample 10. Therefore, theequipotential surface 20-2 is elevated at the outside of the sample 10or the vicinity of the potential correcting electrode 44-1 a and thepotential correcting electrode 44-1 b. In addition, the DC power supply48 b is maintained at voltage (negative voltage having a larger absolutevoltage) lower than the DC power supply 48 a, such that the distributionof the equipotential surface 20-2 elevated at the outside of the sample10 may be higher than at the outside as shown in FIG. 12(A). Further, tothe contrary, the DC power supply 48 b has voltage (a negative voltageor a positive voltage having a smaller absolute value) higher than thatof the DC power supply 48 a, such that the distribution of theequipotential surface 20-2 may be further elevated at the inside. As aresult, the distribution of the equipotential surface 20-2 may becontrolled to be dense by controlling the voltage of the DC power supply48 a and the DC power supply 48 b.

Further, when the sample 10 having a first size, i.e., the wafer of φ300as the sample 10 is installed on the sample stage 11, since there is noneed to apply voltage to the electrode 32-3, the electrode 32-4, thepotential correcting electrode 44-2 a and the potential correctingelectrode 44-2 b, it is preferable to turn-off all of the potentialcorrecting electrode 44-2 b, the switch 36-3, the switch 36-4, theswitch 46-2 a, and the switch 46-2 b connected thereto.

Next, as shown FIG. 12(B), when the sample 10 having a second size,i.e., the wafer of φ450 as the sample 10 is installed on the samplestage 11, voltage is applied to the electrode 32-1 and the electrode32-2 and voltage is also applied to the electrode 32-3 and the electrode32-4. These electrodes are connected with the DC power supply 38-1 andthe DC power supply 38-2 via the switch 36-3 and the switch 36-4 andthese switches 36-3 and switch 36-4 are turned-on to attract the sample10 into the sample stage 11.

In the third embodiment, one ring-shaped potential correcting electrode44-2 is installed in the dielectric part 34 and at the outside of theelectrode 32-2, while in the sixth embodiment, the ring-shaped potentialcorrecting electrode 44-2 a is installed at the outside of the electrode32-4 and the ring-shaped potential correcting electrode 44-2 b isinstalled at the outside thereof. In addition, the potential correctingelectrode 44-2 a and the potential correcting electrode 44-2 b areconnected with the voltage variable DC power supply 48 a and the voltagevariable DC power supply 48 b via the switch 46-2 a and the switch 46-2b and turns-on these switches to apply the negative voltage to thepotential correcting electrode 44-2 a and the potential correctingelectrode 44-2 b. In addition, the DC power supply 48 a and the DC powersupply 48 b are connected to the retarding power supply 26 in series,such that they are maintained at a potential (negative potential havinga larger absolute value) lower than the sample 10. Therefore, theequipotential surface 20-2 is elevated at the outside of the sample 10or the vicinity of the potential correcting electrode 44-2 a and thepotential correcting electrode 44-2 b. In addition, the DC power supply48 b is maintained at voltage (negative voltage having a larger absolutevoltage) lower than the DC power supply 48 a, such that the distributionof the equipotential surface 20-2 elevated at the outside of the sample10 may be higher than at the outside as shown in FIG. 12(B). Further, tothe contrary, the DC power supply 48 b has voltage (a negative voltageor a positive voltage having a smaller absolute value) higher than thatof the DC power supply 48 a, such that the distribution of theequipotential surface 20-2 may be further elevated at the inside. As aresult, the distribution of the equipotential surface 20-2 elevated atthe outside of the sample 10 may be controlled to be dense bycontrolling the voltage of the DC power supply 48 a and the DC powersupply 48 b.

In the sixth embodiment, as shown in FIG. 13, the distribution of theequipotential surface 20-2 is further elevated at the outside by makingthe voltage (a negative voltage having a larger absolute value) of theDC power supply 48 b lower than that of the DC power supply 48 a. As aresult, the equipotential surface 20-1 of the vicinity of the surface ofthe sample 10 becomes the axial symmetry distribution based on theoptical axis as a center and the bending of the primary electron beam 22is removed, thereby preventing the position deviation.

As described above, similar to the first to fifth embodiments, theanalyzer 27 obtains the distance between the optical axis 18 and theouter edge of the sample 10 from a coordinate of an X-Y stage 15 andobtains the setting voltage of the DC power supply 48 a or the DC powersupply 48 b according to the distance, the thickness, and theirradiation condition of the primary electron beam 22 such as theretarding voltage, etc., by applying the shown sample stage 11 to theCD-SEM shown in FIG. 1 and the controller 29 controls the DC powersupply 48 a or the DC power supply 48 b as the setting voltage thereof.Therefore, the sixth embodiment controls the potential of the potentialcorrecting electrode 44-1 a or the potential correcting electrode 44-1 bor the potential correcting electrode 44-2 a or the potential correctingelectrode 44-2 b to prevent the bending of the primary electron beam 22,thereby making it possible to remove the position deviation even in thecase of inspecting the outer peripheral portion of the sample 10.

In addition, it may make the axial symmetry of the distribution of theequipotential surface 20-1 of the vicinity of the surface of the sample10 more excellent by densely controlling the distribution of theequipotential surface 20-2 elevated at the outside of the sample 10.

Further, when the sample 10 having a second size, i.e., the wafer ofφ450 as the sample 10 is installed on the sample stage 11, since thereis no need to apply voltage to the potential correcting electrode 44-1 aand the potential correcting electrode 44-1 b, it is preferable toturn-off the switch 46-1 a and the switch 46-1 b connected thereto.

Therefore, even when the outer peripheral portion of the sample 10 isinspected, the bending of the primary electron beam 22 is removed,thereby preventing the position deviation.

Seventh Embodiment

Next, a seventh embodiment will be described. In the fifth embodiment,the electrode used to attract the sample 10 into the sample stage 11 isfurther protruded than the outer edge of the sample 10, thereby makingit possible to obtain the effect of preventing the position deviationwhen the outer peripheral portion of the sample 10 is inspected.However, the protruded length of the electrode is not described. Theseventh embodiment will describe the length more protruded than theouter edge of the sample 10 of the electrode based on the review resultsby the Inventors.

Hereinafter, only the difference between the seventh embodiment and thefirst to sixth embodiments will be described with reference to FIG. 11and FIGS. 16 to 18.

FIG. 11 is a diagram used in the description of the fifth embodiment andis an enlarged cross-sectional view of the vicinity of the sample stage11 used in the CD-SEM of the embodiment. Further, FIG. 16 showscomponents of the vicinity of the sample stage 11, the shield electrode16 at the same potential as the sample 10, and an objective lens 9 whenthe wafer of φ300 as the sample 10 is installed on the sample stage 11,in particular, components when a position of 1 mm inside from the outeredge of the sample 10 is inspected. Further, FIG. 17 is a graph showingthe relationship between the amount protruded from the sample 10 of theelectrode 32-2 and the bending amount of the primary electron beam 22.In addition, FIG. 18 is an enlarged cross-sectional view of the vicinityof the sample stage 11 used in the CD-SEM of the seventh embodiment andshows the configuration of the DC power supply changed from FIG. 11. Ascan be clearly appreciated from FIG. 11, the DC power supply 38-1 isused with the DC power supply 38-3 of FIG. 1 and the DC power supply38-2 is used with the DC power supply 38-4.

Hereinafter, the seventh exemplary will be described with reference toeach drawing. As described above, FIG. 11(A) is an enlarged view of aconfiguration of the vicinity of the sample stage 11 when the sample 10having a first size, i.e., the wafer of φ300 as the sample 10 isinstalled on the sample stage 11. Similar to the fifth embodiment, theseventh embodiment configures the diameter of the outer edge of theelectrode 32-2 to be larger than that of the sample 10, i.e., the waferof φ300, the DC power supply 38-2 connected thereto is set to thenegative voltage and is connected with the retarding power 26 in series,such that the voltage (a negative voltage having a larger absolutevalue) lower than the retarding voltage is applied to the electrode32-2. As a result, the equipotential surface 20-2 is elevated at theoutside of the sample 10 through the dielectric part 34 from theelectrode 32-2 that is a portion protruded from the sample 10.Therefore, as shown in FIG. 16, the equipotential surface 20-1 of thevicinity of the surface of the sample 10 has the axial symmetrydistribution based on the optical axis as a center and the bending ofthe primary electron beam 22 is removed to prevent the positiondeviation. In addition, when the sample 10 is the sample 10 having afirst size, i.e., the wafer of φ300, since there is no need to applyvoltage to the electrode 32-3 and the electrode 32-4, it is preferableto turn-off the switch 36-3 and the switch 36-4.

Further, as shown in FIG. 16, when the outer peripheral part of thesample 10, i.e., the wafer of φ300, is inspected by applying theconfiguration shown in the seventh embodiment, the measurement position,i.e., the distance X between the optical axis and the outer edge of thesample 10, the length DR1 protruded from the outer edge of the sample 10(that is, the difference between the radius of the outer edge of theelectrode 32-2 and the radius of the sample 10), the radius R1 of thehole of the shield electrode 16 formed in the approximate concentricshape around the optical axis have an effect on the distribution of theequipotential surface 20-1, which has an effect on the bending amount ofthe primary electron beam 22, which is found by the evaluation of theInventors.

As described above, in order to elevate the equipotential surface 20-1falling to the hole of the shield electrode 16 to reduce the bendingamount of the primary electron beam 22, there is a need to elevate theequipotential surface 20-2 from the electrode 32-2. In this case, as theDR1 is wide, the region in which the equipotential surface 20-2 iselevated is wide, thereby strongly elevating the equipotential surface20-2. However, since the equipotential surface 20-1 falling to the holeof the shield electrode 16 is not present in the outside region from thehole of the shield electrode 16, the effect of elevating theequipotential surface 20-2 is not large even though the DR1 is long sothat the outer edge of the electrode 32-2 becomes the outside of thehole of the shield electrode 16 rather than the edge thereof. That is,when the distance X+DR1 from the optical axis 18 to the outer edge ofthe electrode 32-2 is R1 or less, as the DR1 becomes long, the bendingamount of the primary electron beam 22 may be reduced but when the X+DR1is R1 or more, the effect of reducing the bending amount of the primaryelectron beam 22 is saturated.

Next, when the DR1 is changed, the results of the bending amount of theprimary electron beam 22 evaluated by the inventors are shown in FIG.17. FIG. 17(A) is a graph showing the relationship among the amount DR1protruded from the electrode 32-2, the distance X between the opticalaxis 18 and the outer edge of the sample 10, and the bending amount ofthe primary electron beam 22, when the retarding voltage from theretarding power supply 26 is −2200V, the potential of the objective lens9 is +5000V, and a voltage of adding −800V to the retarding voltage fromthe DC power supply 38-2, that is, −3000V is applied to the electrode32-2. A horizontal axis of the graph represents a ratio of the holeradius R1 of the shield electrode 16 to the sum of the amount DR1protruded from the electrode 32-2 and the distance X between the opticalaxis 18 and the outer edge of the sample 10, that is, (DR1+X)/R1 and thevertical axis thereof represents the bending amount of the primaryelectron beam 22. It can be appreciated from FIG. 17(A) that the bendingamount of the primary electron beam 22 is small as the (DR1+X)/R1 islarge, even though the observation position is any of 1 to 3 mm insidefrom the outer edge of the sample 10, but it is converged to any valuein the region where the (DR1+X)/R1 is 1 or more.

Similar to FIG. 17(A), FIG. 17(B) is a graph showing the relationshipbetween the amount DR1 protruded from the electrode 32-2 and the bendingamount of the primary electron beam 22 when the observation position is1 to 3 mm inside from the outer edge of the sample 10. The horizontalaxis is the same as FIG. 17(A) and the vertical axis standardizes thebending amount of the primary electron beam 22 shown in FIG. 17(A) as asaturated value of the bending amount of the primary electron beam 22 atthe observation positions.

It can be appreciated from FIGS. 17A and 17B that the standardizedbending amount of the primary electron beam 22 is converged to about 1in the region where the (DR1+X)/R1 is 1 or more even in any cases. It ispossible to reduce the bending amount of the primary electron beam 22 bymaking the amount DR1 protruded from the electrode 32-2 large from theseresults. To this end, it is effective that sum of the amount DR1protruded from the electrode 32-2 and the distance X between the opticalaxis 18 and the outer edge of the sample 10 is the radius R1 or more ofthe hole of the shield electrode 16.

Further, similar to the graph of FIG. 5 used in the first exemplaryembodiment, the seventh embodiment can reduce the bending amount of theprimary electron beam 22 by lowering the voltage of the DC power supply38-2 (increasing the absolute value of the negative voltage). In thiscase, it is possible to the bending amount of the primary electron beam22 at the voltage of the DC power supply 38-2 smaller than the absolutevalue by making the (DR1+X)/R1 into 1 or more. When the absolute valueof the output voltage of the DC power supply 38-2 is large, the cost ofnecessary DC power supply is problem. As a result, the reduction of theabsolute value of the voltage of the DC power supply 38-2 leads to thecost reduction. For this reason, it is important to widen the amount DR1so that the (DR1+X)/R1 become 1 or more.

Next, as shown in FIG. 11(B), when the wafer of φ450 is installed on thesample stage 11 as the sample 10 having a second size, voltage isapplied to the electrode 32-1 and the electrode 32-2, respectively, bythe DC power supply 38-1 and the DC power supply 38-2. Further, voltageis applied to the ring-shaped electrode 32-3 and the ring-shapedelectrode 32-4. These electrodes are each connected with the DC powersupply 38-3 and the DC power supply 38-4 via the switch 36-3 and theswitch 36-4, and turn-on the switch 36-3 and the switch 36-4 to attractthe sample 10 into the sample stage 11. Even in this case, when thediameter of the outer edge of the electrode 32-4 is configured to belarger than the diameter of the sample 10, i.e., the wafer of φ450 andthe DC power supply 38-4 connected to the retarding power supply 26 inseries is set to the negative voltage, such that the voltage (a negativevoltage having a larger absolute value) lower than the retarding voltageis applied to the electrode 32-4.

As a result, the equipotential surface 20-2 is elevated at the outsideof the sample 10 through the dielectric part 34 from the electrode 32-4that is a portion protruded from the sample 10. Therefore, theequipotential surface 20-1 (not shown) of the vicinity of the surface ofthe sample 10 has the axial symmetry distribution based on the opticalaxis 18 as a center and the bending of the primary electron beam 22becomes small to prevent the position deviation. Even in this case,similar to the sample 10, i.e., the wafer of φ300, the sum of the amountDR1 protruded from the electrode 32-4 protruded from the wafer of φ450and the distance X between the optical axis 18 and the outer edge of thesample 10 is set to the hole radius R1 or more of the shield electrode16, i.e., the (DR1+X)/R1 is set to 1 or more, such that the bendingamount of the primary electron beam 22 can be effectively reduced by thenegative voltage of the DC power supply 38-2 having a smaller absolutevalue, thereby making it possible to prevent the position deviation.

In addition, the DC power supply 38-2 is the voltage fixing DC powersupply in the above-mentioned configuration, but the present inventionis not limited thereto. Therefore, it is preferable that the DC powersupply is variable. In this case, when the wafer of φ300 as the sample10 having a first size or the wafer of φ450 as the sample 10 having asecond size is installed on the sample stage 11, the distribution of theequipotential surface 20-2 is optimized by controlling the voltage ofthe DC power supply 38-2 or the DC power supply 38-4, respectively,thereby making it possible to more effectively reduce the bending of theprimary electron beam 22.

As described above, similar to the first to sixth embodiments, theanalyzer 27 obtains the distance between the optical axis 18 and theouter edge of the sample 10 from a coordinate of an X-Y stage 15 andobtains the setting voltage of the DC power supply 38-2 or the DC powersupply 38-4 according to the distance, the thickness, and theirradiation condition of the primary electron beam 22 such as theretarding voltage, etc., by applying the shown sample stage 11 to theCD-SEM shown in FIG. 1 and the controller 29 controls the DC powersupply 38-2 or the DC power supply 38-4 as the setting voltage thereof.Therefore, the bending of the primary electron beam 22 is prevented bycontrolling the potential of the electrode 32-2 or the potentialcorrecting electrode 32-4, thereby obtaining the effect of removing theposition deviation even in the case of inspecting the outer peripheralportion of the sample 10.

In addition, the seventh embodiment uses the electrode for attractingthe sample 10 into the sample stage 11 in order to prevent the bendingof the primary electron beam 22 such that there is no need to install anew potential correcting electrode, thereby making it possible to obtainthe foregoing effects using the relatively simple structure. Inaddition, since the electrodes 32-1 to 32-4 are at a position lower thanthe bottom surface of the sample 10 and is covered with the dielectricpart 34, there is no risk of interfering or contacting with the sample10. As a result, the seventh exemplary embodiment can obtain an effectof preventing the position deviation when inspecting the outerperipheral portion while effectively installing and attracting thesample 10 on the sample stage 11.

In addition, in the seventh embodiment, as shown in FIG. 11, althoughfour DC power suppliers 38-1 to 38-4 as the power supply applyingvoltage to the electrodes 32-1 to 32-4 are used but the seventhembodiment is not limited to the above-mentioned number. As describedabove, two DC power suppliers 38-1 and 38-2 may be used as shown in FIG.18. FIG. 18 has the same configuration as the sample stage 11 shown inFIG. 11, but the configuration of the power supply applying voltage tothe electrodes 32-1 to 32-4 may be changed.

FIG. 18(A) is an enlarged view of a configuration of the vicinity of thesample stage 11 when the sample 10 having a first size, i.e., the waferof φ300 as the sample 10 is installed on the sample stage 11. The DCpower supply 38-1 and the DC power supply 38-2 are each connected withthe disc-shaped electrode 32-1 and the ring-shaped electrode 32-2,respectively, via the switch 36-1 and the switch 36-2 and turn-on theswitch 36-1 and the switch 36-2 to attract the sample 10 into the samplestage 11. FIG. 18(B) is an enlarged view of a configuration of thevicinity of the sample stage 11 when the sample 10 having a second size,i.e., the wafer of φ450 as the sample 10 is installed on the samplestage 11. By turning-on the switches 36-1 to 36-4, voltage is applied tothe electrode 32-1 and the electrode 32-3 by the DC power supply 38-1set as the positive voltage and to the electrode 32-2 and the electrode32-4 by the DC power supply 38-2 set as the negative voltage, therebyattracting the sample 10 into the sample stage 11.

Therefore, the equipotential surface 20-2 is elevated at the outside ofthe sample 10 through the dielectric part 34 from the electrode 32-2 orthe electrode 32-4 of a portion protruded from the sample 10 and theequipotential surface 20-1 (not shown) of the vicinity of the surface ofthe sample 10 becomes the axial symmetry distribution based on theoptical axis and the bending of the primary electron beam 22 is removed,thereby preventing the position deviation.

Further, in order to rapidly carry the sample 10 after the measurementends by the CD-SEM, it is necessary to weaken the residual adsorptionforce of the sample stage 11 for the sample 10 after the switches 36-1to 36-4 are turned-off. To this end, the effect that the charge amountaccumulated in the attracting part in the region of the positiveelectrode and the attracting part in the region of the negativeelectrode becomes the same is disclosed in Japanese Patent ApplicationLaid-Open Publication No. H10 (1998)-150100.

For this reason, in the seventh embodiment, the radius of the electrode32-1 is a disc of 104 mm, the inner radius of the electrode 32-2 is 108mm, the outer radius of a ring is 159 mm, the inner radius of theelectrode 32-3 is 163 mm, the outer radius of a ring is 198 mm, theinner radius of the electrode 32-4 is 202 mm, and a ring of an outerradius is 234 mm. In addition, the hole radius R1 of the shieldelectrode 16 is 10 mm, the outermost observation position is the 1 mminside from the outer edge thereof, that is, the distance X between theoptical axis 18 and the outer edge of the sample 10 is minimally 1 mm.In this configuration, when the sample 10 is the wafer of φ300, theattracting part in the region of the electrode applied with the positivevoltage is a disc of radius 104 mm and the attracting part in the regionof the electrode having a negative voltage is a ring having the innerradius 108 mm and the outer radius 150 mm and the area of the attractingpart of the positive and negative poles is approximately the same tomake the absolute value of voltage applied to the electrode of each polethe same, thereby weakening the residual adsorption force of the samplestage 11 for the sample 10. In addition, when the distance X between theoptical axis 18 and the outer edge of the sample 10 is 1 mm or more, theratio (DR1+X)/R1 of the sum of the X and the hole radius R1 of theshield electrode 16 and the amount DR1 protruded from the electrode 32-2is 1 or more and the bending of the primary electron beam 22 can bereduced at the negative voltage of the DC power supply 38-2 having asmaller absolute value.

Further, when the sample 10 is the wafer of φ450, the attracting part inthe region of the positive electrode is the disc of radius 104 mm andthe ring of inner radius 163 mm and outer radius 198 mm and theattracting part in the region of the electrode having a negative voltageis the ring of inner radius 108 mm and outer radius 159 mm and the ringof inner radius 202 mm and outer radius 225 mm and the area of theattracting part having the positive and negative poles are approximatelythe same to make the absolute values of voltage of the DC powersuppliers 38-1 to 38-4 the same, thereby making it possible to weakenthe residual adsorption force of the sample stage 11 for the sample 10.Further, when the distance X between the optical axis 18 and the outeredge of the sample 10 is 1 mm or more, the ratio (DR1+X)/R1 of the sumof X and the hole radius R1 of the shield electrode 16 to the amount DR1protruded from the electrode 32-2 is 1 or more and the bending of theprimary electron beam 22 can be reduced by the negative voltage of theDC power supply 38-2 having a smaller absolute value.

In the case of the seventh embodiment, the hole radius R1 of the shieldelectrode 16 is 10 mm, the outermost observation position is the 1 mminside of the sample 10 from the outer edge thereof, that is, thedistance X between the optical axis 18 and the outer edge of the sample10 is minimally 1 mm. In this case, the amount DR1 protruded from theelectrode 32-2 or the electrode 32-4 protruded from the sample 10 is 9mm or more, such that the bending of the primary electron beam 22 can bereduced at the negative voltage of the DC power supply 38-2 having asmaller absolute value. Further, the minimum value of the distance Xbetween the optical axis 18 and the outer edge of the sample 10 is 0 mm,the amount DR1 protruded from the electrode 32-2 or the electrode 32-4is set to be larger than the hole radius R1 of the shield electrode 16,such that the bending of the primary electron beam 22 can be reduced atthe negative voltage of the DC power supply 38-2 having a smallerabsolute value even when the vicinity of the outer edge of the sample 10is observed.

Further, in the seventh embodiment, the electrodes 32-1 to 32-4 areformed to have the above mentioned dimension, but are not limitedthereto.

Further, in the seventh embodiment, in order to make the bending of theprimary electron beam 22 at the negative voltage of the DC power supply38-2 having a smaller absolute value small, the amount DR1 protrudedfrom the electrode 32-2 is wide in order to make the (DR1+X)/R1 largerthan 1. On the other hand, even though the protruded amount DR1 is longso that the (DR1+X)/R1 is 1 or more, since the bending amount of theprimary electron beam 22 is not changed, the upper limit of theprotruded amount DR1 is not limited in terms of the bending amount ofthe primary electron beam 22. However, in order to measure the sample 10having two or more kinds of sizes, it is necessary that the protrudedamount DR1 is the difference or less between the radius of the sample 10having the maximum size and the radius of the sample 10 having theminimum size.

Eighth Embodiment

Next, an eighth embodiment will be described. In the seventh embodiment,the electrode used to attract the sample 10 into the sample stage 11 isfurther protruded than the outer edge of the sample 10, thereby makingit possible to obtain the effect of preventing the position deviationwhen the outer peripheral portion of the sample 10 is inspected. In theseventh embodiment, four sheets of electrodes 32-1 to 32-4 are installedin the dielectric part 34. On the other hand, the eighth embodiment usesthree sheets of electrodes to meet the inspection of the sample havingdifferent sizes, thereby making it possible to prevent the bending ofthe primary electron beam 22 when the inspection of the outer peripheralportion of the sample 10 is performed. Hereinafter, only the differencebetween the eighth embodiment and the first to seventh embodiments willbe described with reference to FIGS. 19 and 20.

FIG. 19 is an enlarged diagram of the vicinity of the sample stage 11 ona movement mechanism, i.e., the stage 15 used in a CD-SEM of the eighthembodiment. Herein, FIG. 19(A) is a diagram showing the configuration ofthe vicinity of the sample stage 11 when the sample 10 having a firstsize, i.e., the wafer of φ300 as the sample 10 installed on the samplestage 11 and the sample 10 having a second size, i.e., the wafer of φ450as the sample 10 are installed on the sample stage 11, respectively. Inaddition, FIG. 20 is a diagram showing a cross section of line C-C ofthe sample stage 11 of FIG. 19. Further, in order to easily recognizethe positional relationship, the outer edge of the sample 10, i.e., thewafer of φ300 or the wafer of φ450 is shown by a dotted line.

As shown in FIG. 19(A), the DC power supply 38-1 set as the positivevoltage and the DC power supply 38-2 set as the negative voltage areeach connected with the disc-shaped electrode 32-1 and the ring-shapedelectrode 32-2, respectively, via the switch 36-1 and the switch 36-2and turn-on the switch 36-1 and the switch 36-2 to attract the sample 10into the sample stage 11. In this case, similar to the fifth embodimentand the seventh embodiment, the outer edge of the electrode 32-2 isconfigured to be further protruded than the outer edge of the sample 10having a first size, i.e., the wafer of φ300. In addition, the DC powersupply 38-2 set as the negative voltage is connected with the retardingpower supply 26 in series, such that the electrode 32-2 is applied withvoltage (negative voltage having a larger absolute value) smaller thanthe retarding voltage. As a result, the equipotential surface 20-2 iselevated at the outside of the sample 10 through the dielectric part 34from the electrode 32-2 that is a portion protruded from the sample 10.

In addition, as described in the seventh embodiment, when the distancebetween the optical axis 18 and the outer edge of the sample 10 is X,the hole radius of the shield electrode 16 is R1, and the amountprotruded from the electrode 32-2 is DR1, it is important to set the(DR1+X)/R1 to 1 or more. Therefore, even when the outer peripheralportion of the sample 10 is inspected, the equipotential surface 20-1(not shown) of the vicinity of the surface of the sample 10 has theaxial symmetry distribution based on the optical axis as a center andthe bending of the primary electron beam 22 is suppressed to prevent theposition deviation.

Next, the configuration when the wafer of φ450 is installed on thesample stage 11 as the sample 10 having a second size will be describedwith reference to FIG. 19(B). In this case, the polarity of the DC powersupply 38-1 and the DC power supply 38-2 connected to the retardingpower supply 26 in series are inverted to the case of FIG. 19(A), suchthat the DC power supply 38-1 is set to a negative voltage and the DCpower supply 38-2 is set to the positive voltage. Voltage is applied tothe electrode 32-1 and the electrode 32-2, respectively, by turning-onthe switch 36-1 and the switch 36-2 connected to each of the powersupply and voltage is applied to the ring-shaped electrode 32-3 byturning-on the switch 36-3 connected to the DC power supply 38-1. Inthis case, the DC power supply 38-1 set as the negative voltage isconnected with the retarding power supply 26 in series, such that theelectrode 32-3 is applied with voltage (a negative voltage having alarger absolute value) smaller than the retarding voltage. As a result,the equipotential surface 20-2 is elevated at the outside of the sample10 through the dielectric part 34 from the electrode 32-3 that is aportion protruded from the sample 10. In addition, as described above,it is important to set the (DR1+X)/R1 to 1 or more. In this case, thebending of the primary electron beam 22 can be reduced at the negativevoltage of the DC power supply 38-2 having a smaller absolute value.

In addition, the eighth embodiment can suppress the sheet of theelectrode installed in the dielectric part 34 to three sheets and canobtain the foregoing effects using a simpler configuration than theseventh embodiment. In addition, after the inspection process, it isimportant to remove the residual adsorption of the sample 10 into thesample stage 11 after turning-off the switches 36-1 to 36-3. To thisend, it is preferable that the areas of each of the positive andnegative electrodes opposite to the sample 10 are the same. For thisreason, in the eighth embodiment, the positive voltage is applied to theelectrode 32-1 and the negative voltage is applied to the electrode 32-2when the wafer of φ300 as the sample 10 is inspected, while the negativevoltage is applied to the electrode 32-1 and the electrode 32-3 and thepositive voltage is applied to the electrode 32-2 when the wafer of φ450as the sample 10 is inspected. Therefore, when the sample 10 having eachsize is inspected, the areas of each of the positive and negativeelectrodes opposite to the sample 10 are the same, such that it ispossible to remove the residual adsorption into the sample stage 11 forthe sample 10 after the inspection process is performed and the switches36-1 to 36-3 are turned-off.

In detail, the hole radius R1 of the shield electrode 16 is 10 mm, theradius of the electrode 32-1 is a disc of 104 mm, the electrode 32-2 isa ring of inner radius 108 mm and outer radius 189.2 mm, and theelectrode 32-3 is a ring of inner radius 193.2 mm and outer radius 234mm. In this configuration, when the sample 10 is the wafer of φ300, theattracting part in the region of the electrode applied with the positivevoltage is a disc of radius 104 mm and the attracting part in the regionof the electrode having a negative voltage is a ring having the innerradius 108 mm and the outer radius 150 mm and the area of the attractingpart of the positive and negative poles is approximately the same tomake the absolute value of the DC power supply 38-1 and the DC powersupply 38-2 the same, thereby weakening the residual adsorption force ofthe sample stage 11 for the sample 10. In addition, for example, whenthe distance X between the optical axis 18 and the outer edge of thesample 10 is 1 mm, the (DR1+X)/R1 is 1 or more and the bending of theprimary electron beam 22 can be reduced at the negative voltage of theDC power supply 38-2 having a smaller absolute value.

In addition, when the sample 10 is the wafer of φ450, the adsorptionpart in the area of the electrode applied with a positive voltage is aring of an inner radius 108 mm and an outer radius 189.2 mm. On theother hand, the adsorption part in the region of the electrode appliedwith the negative voltage is a disc of radius 104 mm and a ring of innerradius 193.2 mm and an outer radius 225 mm. As a result, the areas ofthe adsorption part of the positive and negative poles are approximatelythe same to make the absolute value of the voltage of the DC powersupply 38-1 and the DC power supply 38-2 the same, thereby making itpossible to weaken the residual adsorption force of the sample stage 11for the sample 10. In addition, for example, when the distance X betweenthe optical axis 18 and the outer edge of the sample 10 is 1 mm, the(DR1+X)/R1 is 1 or more and the bending of the primary electron beam 22can be reduced at the negative voltage of the DC power supply 38-2having a smaller absolute value.

Further, in the eighth embodiment, the electrodes 32-1 to 32-3 areformed to have the above mentioned dimension, but are not limitedthereto.

In the eighth embodiment, since the electrodes 32-1 to 32-3 are at aposition lower than the bottom surface of the sample 10 and is coveredwith the dielectric part 34, there is no risk of interfering orcontacting with the sample 10. As a result, the eighth exemplaryembodiment can obtain an effect of preventing the position deviationwhile effectively installing and attracting the sample 10 on the samplestage 11.

In addition, the first to eighth embodiments install the wafer of φ300and φ450 as the sample 10 having different sizes on the sample stage 11but are not limited thereto. As a result, the wafer of φ200 and thewafer of φ300 may be used.

In addition, the first to eighth embodiment describe, for example, theCD-SEM as the inspecting apparatus using the primary electron beam butare not limited thereto. The present invention is applied to otherinspecting apparatuses using the primary electron beam, which preventsthe bending of the primary electron beam to obtain the effect ofremoving the position deviation by preventing the bending of the primaryelectron beam, similar to the present invention.

In addition, the first to eighth embodiment describe, for example, theinspecting apparatus using the primary electron beam as the chargedparticles but are not limited thereto. For example, the presentinvention can be applied to a microscope using ions such as helium orlithium, etc. In this case, unlike the first to sixth embodiments, sincethe charged particles have the positive potential, they have thepolarity and value suitable for measuring the retarding potential or thepotential correcting electrode applied to the sample to prevent thebending of the charged particles to obtain the effect of removing theposition deviation.

In addition, the first to eighth embodiment describe, for example, theinspecting apparatus as a charged particle beam application apparatus,but are not limited thereto. For example, the present invention isapplied to the primary electron beam drawing apparatus forming theelectron circuit pattern by irradiating the primary electron beam on thewafer applied with the photosensitive material to prevent the bending ofthe charged particles to obtain the position deviation similar to thepresent invention.

INDUSTRIAL APPLICABILITY

As described above, the present invention can prevent the bending of thecharged particle beam such as the primary electron beam when inspectingthe vicinity of the outer edge of the sample, thereby making it possibleto remove the position deviation. Further, the present invention obtainsthe same effect even when inspecting the sample having different size,which may be usefully used for the semiconductor inspecting apparatus.

EXPLANATION OF REFERENCE NUMERALS AND SYMBOLS

-   1 . . . ELECTRON GUN-   2 . . . EXTRACTION ELECTRODE-   3 . . . CONDENSER LENS-   5 . . . SCANNING DEFLECTOR-   6 . . . APERTURE-   8 . . . E CROSS B DEFLECTOR-   9 . . . OBJECTIVE LENS-   10 . . . SAMPLE-   11 . . . SAMPLE STAGE-   14 . . . SECONDARY ELECTRON DETECTOR-   15 . . . X-Y STAGE-   16 . . . SHIELD ELECTRODE-   18 . . . OPTICAL AXIS-   22 . . . PRIMARY ELECTRON BEAM-   24 . . . SECONDARY ELECTRON-   26 . . . RETARDING POWER SUPPLY-   27 . . . ANALYZER-   29 . . . CONTROLLER-   32 . . . ELECTRODE-   34 . . . DIELECTRIC PART-   35 . . . METAL BASE-   38 . . . DC POWER SUPPLY-   40 . . . CONTACT PIN-   42 . . . SWITCH-   44 . . . POTENTIAL CORRECTING ELECTRODE-   46 . . . SWITCH-   48 . . . DC POWER SUPPLY-   50 . . . GROOVE-   52 . . . INSULATOR-   54 . . . CONCAVE PORTION

1. A measurement or inspecting apparatus, the apparatus comprising: asample stage holding a sample; a unit moving the sample stage; a beamsource irradiating a charged particle beam on a surface of the sample; abeam scanning unit scanning the charged particle beam on the surface ofthe sample; a first potential correcting electrode installed at aposition lower than a surface holding the sample of the sample stage,and at an outside of an outer edge of the sample; a first voltage supplysource applying voltage to the first potential correcting electrode; anda controller controlling the voltage of the first voltage supply source.2. The measurement or inspecting apparatus according to claim 1, furthercomprising: a retarding power supply source applying a retarding voltageto the sample, wherein the first voltage supply source and the retardingpower supply source are electrically connected in series.
 3. Themeasurement or inspecting apparatus according to claim 1, furthercomprising: a second potential correcting electrode installed at aposition lower than the surface holding the sample of the sample stage,and at an outside of an outer edge of the first potential correctingelectrode; and a second voltage supply source applying voltage to thesecond potential correcting electrode, wherein the controller controlsthe voltage of the second voltage supply source.
 4. The measurement orinspecting apparatus according to claim 1, further comprising: a firstattracting electrode and a second attracting electrode attracting thesample, being installed within the sample stage.
 5. The measurement orinspecting apparatus according to claim 1, wherein the first potentialcorrecting electrode is a ring-shaped electrode.
 6. The measurement orinspecting apparatus according to claim 1, further comprising: anobjective lens converging the charged particle beam on the sample; adeflector deflecting a secondary electron generated from the sample,being installed at a beam source side of the objective lens, and adetector detecting the secondary electron deflected by the deflector,being installed at a beam source side of the deflector.
 7. Themeasurement or inspecting apparatus according to claim 6, furthercomprising: a shield electrode which has a hole passing the chargedparticle beam, being installed between the objective lens and the samplestage.